Vibratory aircraft alarm of the rotary eccentric weight type



Sept. 4, 1951 1 M GREENE 2,566,409

VIBRATORY AIRCRAFT ALARM 0F THE ROTARY ECCENTRIC WEIGHT TYPE Filed OCT'.21, 1949 64 JNVENTOR. 1 l I 6o MOTOR so/wmp M Gase-Ne- L BY PatentedSept. 4, 1951 f6 Glahns. -1 This invention relates to yvbratoljyaiclldit .alarms of .therotary eccentric weightliype.

:By Way of .examnleniylnvention is described herein with .respect .to.an ,aircraftstick shaker,

.,i. 5e.. azshaker for .the control .stick rof-anaircraft,

the invention being particularly ,Well tsuited .for this .purposevHowever, .it `is `to .be .understood that this specic VILform of -myrinve.ntiolrris only .to

be consideradas .illustrative .and my inrentiongis .not to "be .deemed`-as 'limited ,thereby except to the extent .to which features .of suchembodiment .are .pointedout belowand areemcornorfateoinathe :amendedclaims lIt anbbiect vof A.my .invention fto provide an alarm .of .thecharacter .described which .is cornand .rugged and which .in lmounted:..oosition loocu.niesa comparatively. smallsoace.

,ft is vanother object oimycinvention Ato vprovide an alarm of thecharacterdesoribed which 4^con- A`stitutes Irelatively few and .simpleparts .and is vecono.rncal v*to xmanufacture .and easy V to install.

ln 'the Specific embodiment .of the ,invention hereinafter ,setfortnanelectric motor is used to the .eccentric weight. .If the weight weremounted to ,turn about .the .motor .sbaftoonsiderablefspace would beoccupied because .the weight .ld .have a Ltnrowlconsiderably .in-.excessof ,the di .ance from the .motor .shaft .to .tne-.oblectfon 'which .the`.inotor was mounted. This woulden-n tail displacing the ,motor topermit .the .eccentric to clear .the object. r.there `is .very littleafreesnace .in .tbe `region of the control .stick off v.an `.aircraft4so that, if the `stick Shaker should .have :the ...eccentric weightturning .about the motorrsna'ftothe Astiel: shaker `might lbe 4sovbulls-y .that lit .could Enot 'be used practically.

.It lis `an oblectoi the .present invention wto nro- -vide ,an `alarm.of the .character .described .which .is specially adapted to be mountedon .slender objects .being `of such construction as :to take :up jlessspace than it would if .the :eccentric weight lwere mounted .to .turnabout the motor shaft.

@ther objects of my ,invention Will in part .be obvious and in part willbe .pointed ,out hereinafter.

My invention accordingly Consists .in the feal tures .o f construction,.combinations 'of elements and arrangements .of parts .which will -beenernpliB fied in the device hereinafter ,described rand .of which .1511.Scope .of application will be indicated in the appended .clanns .ln theaccompanying drawings .-in which is Shown one of the various possibleembodiments of my invention;

w2 control :stick having mounted thereon vo stick :shaker constructed inaccordance vwith my inven- Ltion; .and

Fig. L2 iis .a :sectional view taken substantially along thellineZ-fzof'Flg. 1.

Referring .now in detail to the drawings, the reference .numeral il!!:denotes a control .stick 'o'f an :aircraft As iis conventionalthisstick is icon- 4.nested .through .suitable mechanisms, for example,wires or servomotors to the control .surfaces of vthe ,aircraft .so.that the .stick .through its :positiongovernsmovement. of the aircraft.

The stick includes a :shaft .I2 and a handle .HL Aboth 'of which arel.of standard construction. :It .may ;b,.e .mentioned ihere .thatyarious types o'f .shaft ,contoursconventionallyare used. For example,some shafts are straight, as shown, from the point of .supnorttothehandle. Othershafts .are curved .at ,various `portions of theirlengths. Thus, one wellknown v.type .of .shaft is `curved at lbothYends, .the curvaturesbelng .in opposite directions .so that the :shaftresembles a `modified s. The vhandle .is removably mounted on the tip ofthe shaft by any suitable fastening means, Afor l' .examplebya few bolts.tnot shown) The .reference .numeral ILE .denotes :the control :stickshaker. .Said 4shaker ,inludes amounting member which is designed to beslipped on .and secured .to ,the shaft. .To this end the mounting memberAis .hollow and .open-ended, ,and conveniently, as'shown, .may take .theform of a 'tubular sleeve .IB whose .diameter is sufliciently large to'enable ,it ,to be slipped on Athe .shaft of the .controlstick.`Itmay1be observed ithat where the stick has a curved handle end .the.internal diameter .of the ,sleeve should be l'sufficiently large,taking into Aaccount the length of the sleeve, tofperm'it the sleeve ltobe slid vover this curved portion of theshat.

'The lower end of 'fthe sleeve is provided with a plurality of tappedapertures 20 designed to rece'lveset-screws 22 that are employeddetachably totfasten the stiel.- shaker-to the shaft. If desired, theseopenings can be reinforced by a flange .24.

The sleeve vserves :as a support for an anti lfri-lotion'hearing :216which comprises an vinner race 2.8, yan outer :race 43l) and 'a set lofballs 32 :rolling on and between the races. The yinner .race l2.8 isfirmly secured to .the Vsleeve I8., for .instance by :being force-fittedthereon, so that the outer race 3,0 -is :rotatable .about the axis ofsymmetry of the sleeve. A vring .gear 34 is vrmly securedto the outer.race 30 e. g. by vforce-fitting, 'so as -to turn therewith about .saidaxis of `the sleeve.

'1 vvis a :phantom perspcotivegof.anarcraft All The ring gear carries aneccentric weight .36

which is firmly attached thereto, for instance by means of screws 38.Any suitably configured weight can be used, the one illustrated hereinextending over approximately 120 of the circumference of the gear. Saidweight, for compactness, is in the shape of a tubular sector.

The ring gear, ball bearing and eccentric weight are contained in ahousing constituting a base plate 4D which is permanently mounted on thesleeve i8 by a force-fit and a sheet metal cover 42 fashioned in theshape of a cup with its rim accommodating the base plate and attachedthereto as by screws 44. The opposite end of the cover is apertured topass the shaft I2 and may be seated on an annular shoulder 46 formed onthe upper end of the sleeve.

The gear 34 meshes with a pinion 48 mounted on the output shaft 50 of anelectric motor 52. The base of said motor is fastened, as by screws 54,to an extension 56 on the lower end of the sleeve I8. The motor andpinion are concealed by a sheet metal cover 58 secured, as by screws 80,to the extension 56. The motor is of the high speed fractional horsepower type inasmuch as spinning the eccentric weight does not require alarge torque. Accordingly, the diameter of the motor is considerablysmaller than the diameter of the path travelled by the eccentric weightand. indeed, may be smaller than the diameter of the control stickshaft.

It will be appreciated that by thus orbiting the weight about the hollowcenter member in which a control member can be disposed and on which themotor is supported, a savings in space is effected which is sosubstantial that for the first time it is practical to employ a rotatingWeight in the limited space in which it may be disposed as a stickshaker for aircraft. Y

Moreover, with the arrangement described, the size of the weight, andtherefore the amplitude of the shaking effect, can be increased to anydesired magnitude without interfering with other parts of the aircraftor cramping the movements of the pilot. V

In addition, the mounting of the weight as set forth hereinaboveeliminates the tendency of the weight to twist the member on which it ismounted as it does when the weight is mounted to turn about an axisalongside the support.

Electric energy is supplied to the motor from any suitable source ofelectric power, as for example a battery 62, the electricity being ledthrough feed wires G4, one of which is interrupted by a normally openswitch 65 that is controlled by a condition responsive device, that isto say, a device which upon the occurrence of a condition moves from oneposition to another. Preferably the condition is one of imminent danger.A typical device of this character is shown in my Patent No. 2,478,967,which is dated August 16, 1949, which closes a switch when an aircraftreaches an attitude immediately preceding stall.

It thus Will be seen that I have provided a device which achieves allthe objects of my invention and is well adapted to meet the conditionsof practical use.

As various possible embodiments might be made of the above invention,and as various changes might be made in the embodiment above set forth,it is to be understood that all matter herein described, or shown in theaccompanying drawings, is to be interpreted as illustrativeand not in alimiting sense.

Having thus described my invention, I claim as new and desire to secureby Letters Patent:

1. In an aircraft having a control stick shaft, a source of electricenergy, a switch, and a condition-responsive device which upon theimminence of danger closes said switch: a stick shaker, said stickshaker including a sleeve encircling said shaft, means to detachablysecure said sleeve to said shaft, an anti-friction bearing having aninner race, an outer race and rolling elements between said races, theinner race being firmly fixed to said sleeve, a gear rmly fixed to theouter race, said bearing rotating about the axis of symmetry of thesleeve, a weight mounted to turn with said gear, said weight beingdisposed eccentrically of said axis, a pinion meshing with said gear, anelectric motor mounted on said sleeve, said pinion being secured to theoutput shaft of the motor, and circuit means connecting said source tosaid motor through said switch.

2. In an aircraft having a control stick shaft, a source of electricenergy, a switch, and a condition-responsive device which upon theimminence of danger closes said switch: a stick shaker, said stickshaker including a sleeve encircling said shaft, means to secure saidsleeve to said shaft, an anti-friction bearing having an inner race, anouter race and rolling elements between said races, the inner race beingfirmly fixed to said sleeve, a gear firmly fixed to the outer race, saidbearing rotating about the axis of symmetry of the sleeve, a weightmounted to turn with said gear, said weight being disposed ecoentricallyof said axis, a pinion meshing with said gear, an electric motor mountedon said sleeve and arranged to turn said pinion, and circuit meansconnecting said source to said motor through said switch.

3. In combination in an aircraft, a control stick having a shaft, astick shaker, said stick shaker including a sleeve encircling saidshaft, means to secure said sleeve to said shaft, an antifrictionbearing having an inner race, an outer race and rolling elements betweensaid races, the inner race being firmly fixed to said sleeve, a gearfirmly fixed to the outer race, said bearing rotating about the axis ofsymmetry of the sleeve, a Weight mounted to turn with said gear, saidweight being disposed ecoentrically of said axis, a pinion meshing withsaid gear, and an electric motor mounted on said sleeve, said pinionbeing secured to the output shaft of the motor.

4. An aircraft signalling device adapted to impart a shaking effect to acontrol element of an aircraft, said device comprising a sleeve whereinsaid element is disposed, means to secure said sleeve to said controlelement, an anti-friction bearing having an inner race, an outer raceand rolling elements between said races, the inner race being firmlyfixed to said sleeve, a gear firmly fixed to the outer race, saidbearing rotating about the axis of symmetry of the sleeve, a Weightmounted to turn with said gear, said weight being disposed ecoentricallyof said axis, a pinion meshing with said gear, and an electric motormounted on said sleeve and arranged to turn said pinion, said pinionbeing secured to the output shaft of the motor.

5. An aircraft signalling device adapted to impart a shaking effect to acontrol element of an aircraft, said device comprising a mounting memberhaving an opening wherein said control element is disposed, means forsecuring said mounting member to said controhelement, a weight,

means to mount said weight on said mounting member eccentrically of thecentral axis of said opening for rotation relative to said member aboutsaid axis to produce the shaking effect, and a motor to rotate saidWeight.

6. An aircraft signalling device adapted to impart a shaking eifect to acontrol element of an aircraft, said device comprising a mounting memberhaving an opening wherein said control element is disposed, means forsecuring said mounting member to said control element, a Weight, andmeans to mount said weight on said mounting member eccentrically of thecentral axis of said opening for rotation relative to said mountingmember about said axis to produce the shak- 15 2,258,747

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATEN'I'S Number Name Date 1,881,878 Nidy Oct. 1l, 19322,060,806l Hunt v .1 ;1 Nev. 17, 1936 2,128,250 Harvard et a1. Aug. 30,1938 Daan@ oet; 14,

